The mission of the NIEHS Microarray Core (NMC) is to utilize advances in genomic and bioinformatic technologies to enable Intramural NIEHS scientists to pursue studies that address how the environment influences human health. The NMC continuously strives to develop and implement new analytical and computational approaches to investigate genome-wide changes in gene expression. Specific technical accomplishments include testing and optimization of RNA isolation and amplification protocols to perform microarray experiments with RNA from limited tissue sources e.g laser capture microdissected and embryonic samples. The NMC also incorporated a new gene expression platform (Illumina) and optimized the utilization of microarray technologies that extend the capacity to explore genome-wide analyses such as chromatin immunoprecipitation coupled with microarray chips (ChIP-chip) and microRNA (miRNA) applications. The installation and implementation of software packages (e.g. Agilent DNA Analytics and Affymetrix GeneChip Command Console) for emerging and existing genomic technologies has greatly improved the bioinformatics capacity of the NMC. In addition, continuing modifications to the NIEHS Microarray Core custom in-house MicroArray Project System (MAPS) have ensured that the NMC can sufficiently track and manage sample and experimental information related to microarray analyses. Finally, the NMC has continued to refine a rigorous QA/QC protocol incorporated into a standard deliverable that is distributed upon completion of a project.